Field of the Disclosure
The disclosure relates to a power supply apparatus, and relates particularly to a power supply apparatus with cable voltage drop compensation.
Description of Related Art
Typically, most power supply apparatuses are coupled to a load (for example, a cell phone, a table PC, a notebook computer, a portable power source and such electronic device) through a power cable, so as to supply power (or charge) to the load. However, a power cable itself usually has impedance. When the load increases such that the current passing through the power cables become large, the impedance of the circuit of the power cable itself or the plug of the power cable will generate a noticeable voltage drop. Because an output voltage provided by a power supply apparatus is typically a set value, therefore a load voltage transmitted to a load terminal through the power cable will drop with an increase in the current. In this way, whether an electronic device at the load terminal will operate normally (or charge) or not may be affected. Particularly, once the voltage drop generated on the power cable is too large such that the load voltage value received by the load terminal drops below a minimum operating voltage value that is allowable for the electronic device, then the electronic device at the load terminal will stop operating.
Therefore, in general applications, typically an additional sensing wire will be adopted to connect to the load terminal, so as to sense the load voltage of the load terminal. However, the additional sensing wire may reduce the reliability of the power cable and increase cost of the power cable. Therefore, under the premise of not adopting an additional sensing wire, how to lower the influence the voltage drop on the power cables has on the voltage at the load terminal such that the stability of the voltage at the load terminal may be enhanced is still an issue which a person skilled in the art is faced with.